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DEVELOPMENT OF QUALITY CONTROL SYSTEM FOR DIAGNOSTIC X-RAY UNITS TO AIM REDUCTION OF PATIENT DOSE

开发诊断 X 射线设备的质量控制系统以减少患者剂量

基本信息

批准号：
15590458
负责人：
MATSUMOTO Masao
金额：
$ 2.24万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15590458/
关键词：
High resolution Schottky CdTe detector Diagnostic x-ray spectrum Monte Carlo simulation method Stripping procedure Rise time discrimination (RTD) circuit コンプトン散乱法乳房用X線装置 X線CT装置高分解能CdTe検出器診断用X線装置 stripping法一次X線スペクトル 90°散乱X線スペクトル

项目摘要

The purpose of this study is to measure diagnostic x-ray spectra using a high resolution Schottky CdTe detector (TOYO MEDIC RAMTEC 413A) and to determine the best response function of CdTe detector for correcting the measured spectra with using a rise time discrimination (RTD) circuit to primary x-ray spectra. Since the measured spectra were distorted by the response of CdTe detector and did not present the true photon spectra, the correction by the stripping procedure was applied. The response function of CdTe detector has been determined by using Monte Carlo simula-tion method for calculating the photon interaction (K-escape, coherent scattering and Compton scattering) and incomplete charge collection by trapping of hole and use of RTD circuit. This simulation performed with various important factors (mean path length. λ_h of hole and weight factor W_q of incomplete charge collection) for finding the best response function. The photon spectra corrected with those various response functions were compared with the corrected photon spectra measured using a high purity Ge (HP-Ge) detector (PRINCETON GAMMA-TECH NIGP1013345), and the Al-attenuation curves calculated from corrected spectra and measured using the HP-Ge detector were compared. The best-fitted response function was determined, and the attenuation curves calculated from the spectra corrected with this response function were agreed with that measured using the HP-Ge detector within maximum error 0.03 of the attenuation rate and 5.0 % of the half value layer.

本研究的目的是使用高分辨率肖特基CdTe探测器（TOYO MEDIC RAMTEC 413 A）测量诊断X射线谱，并确定CdTe探测器的最佳响应函数，用于使用上升时间鉴别（RTD）电路对初级X射线谱进行校正。由于测量的光谱被CdTe探测器的响应所扭曲，并且不呈现真实的光子光谱，因此应用剥离程序进行校正。本文用Monte Carlo模拟方法计算了CdTe探测器的光子相互作用（K-逃逸、相干散射和康普顿散射）和空穴俘获引起的不完全电荷收集，并利用RTD电路确定了探测器的响应函数。该模拟使用各种重要因素（平均路径长度）进行。孔的λ_h和不完全电荷收集的权重因子W_q）来寻找最佳响应函数。将用这些不同响应函数校正的光子光谱与使用高纯度Ge（HP-Ge）检测器（PRINCETON GAMMA-TECH NIGP 1013345）测量的校正的光子光谱进行比较，并且将从校正的光谱计算的Al衰减曲线与使用HP-Ge检测器测量的Al衰减曲线进行比较。确定了最佳拟合的响应函数，用此响应函数校正后的衰减曲线与HP-Ge探测器测量的衰减曲线在衰减率的最大误差为0.03和半值层的5.0%以内一致。